A METHOD OF MANUFACTURING CURVILINEAR STRUCTURES AND STRUCTURES FORMED THEREBY

Abstract: A method of manufacturing structures comprising the steps of: (a) forming a first mould having a release surface; (b) applying plaster to the release surface of the first mould to produce a second mould (13); (c) removing the second plaster mould (13) from the first mould to reveal a finished surface (15) produced by contact with the release surface; (d) arranging the second plaster mould (13) in a desired position away from the first mould; and (e) applying a reinforcing layer (21) onto the opposite surface (23) of the plaster mould (13) to the finished surface (15) such that the reinforcing layer (21) cures and bonds to the plaster mould (13) to produce a structure having an integral finished plaster surface (15). Structures, such as houses and other buildings, can be easily, cheaply and quickly erected using this method. Further, the resulting structures are provided with a well finished interior surface which may be readily decorated.

Description: A METHOD OF MANUFACTURING CURVILINEAR STRUCTURES AND STRUCTURES FORMED THEREBY This invention relates to a method of manufacturing structures, such as buildings having curvilinear forms, and to structures formed using the method. It is obviously well known to erect buildings using bricks and mortar and to shape the buildings as desired by arranging the bricks in the appropriate places. However, when buildings or other structures having a complicated curvilinear form are required, it becomes very difficult and expensive to erect them using bricks and normal building techniques. Furthermore, when a brick or block built structure is completed, the interior surface thereof usually needs to be plastered or lined in some way to give an attractive and aesthetic finish. Prior art dome-shaped structures, such as mud huts, have been made by forming an initial frame, sometimes of wood, wire or chicken mesh, and overlaying the frame with mud, reeds or some combination thereof. Such huts are very solid and sound, but tend to be very simple in design and are time-consuming to erect. Larger and more intricate curvilinear structures tend to require a complicated support framework or buttresses, etc. A radical departure from .these known prior art methods of manufacturing structures has been developed by the present inventor. In this regard, the present inventor has formed structures having extremely complicated curvilinear forms by manufacturing a series of moulds, placing the moulds in position, adding additional mould structure where necessary, applying a layer of concrete or the like to the mould and then dismantling the mould from inside the structure and removing it therefrom. Although this technique has been successful, many of the moulds must be dismantled or destroyed before they can be removed from the structure after moulding and, furthermore, the internal surface of the final structure is sometimes very rough, with pits and cracks where the moulds have been broken away. Hence, the present invention has been developed to improve significantly upon the inventor's own prior art technique, and fundamentally over the other known prior art mentioned above. In the light of the foregoing, the present invention provides a method of manufacturing structures comprising the steps of: (a) forming a first mould having a release surface; (b) applying plaster or a plaster substitute to the release surface of the first mould to produce a second mould; (c) removing the second mould from the first mould to reveal a finished surface produced by contact with the release surface; (d) arranging the second mould in a desired position away from the first mould; and (e) applying a reinforcing layer onto the opposite surface of the second mould to the finished surface such that the reinforcing layer cures and bonds to the second mould to produce a structure having an integral ' finished plaster or plaster substitute surface. As a result of the present invention, complicated curvilinear structures can be readily manufactured and assembled. With this in mind,, due to the second mould being formed of plaster or a plaster substitute, portions thereof can be readily removed to adjust the shape of the mould, if necessary. The term "plaster substitute" means any suitable material having the necessary properties to carry out the described method and provide a finished surface after removal of the second mould from the first mould. Preferably a plurality of the second moulds are produced either from the same first mould or from different first moulds. The resulting second moulds are then assembled in a desired configuration to produce a larger structure. Alternatively, if it is possible to do so, an entire structure can be formed using a single second mould; such a structure would, of course, be relatively simple and small. By arranging a plurality of second moulds adjacent to each other, a complete house or other building can be produced and it is simply necessary to apply the reinforcing layer over the moulds to give the house its desired strength and rigidity. Before the reinforcing layer is applied to the second mould or moulds, electrical wiring or ducting for wiring, plumbing or any other internal appliance may be fitted. Once again, the relatively weak nature of the plaster mould facilitates the installation of such services and devices. Once the reinforcing layer has been applied to the complete structure, however, the services are held rigidly, firmly and reliably. The external surface of the plaster mould may in some circumstances also be sealed, for example by Shellac, before applying the reinforcing layer in order to improve adhesion of the reinforcing layer to the plaster mould. The reinforcing layer is preferably a concrete, more preferably a sprayed concrete such as gunite (also known as shotcrete) . Other suitable reinforcing materials could also be used, such as glass fiber, mud (in certain countries having an appropriate climate) , etc. Furthermore, a weak fibreglass shuttering could be applied to the plaster mould to receive concrete poured over the second mould. Sprayed gunite is, however, probably the most practical and convenient reinforcing material to use. The first mould preferably has a surface treatment or skin over its surface to ensure that the finished surface of the second mould releases easily from the first mould. In this way, a high quality finished surface can be produced on the second mould. The release surface of the first mould is preferably a . silicone rubber skin. Other suitable release materials could, of course, alternatively be used. If gunite is used, it is sprayed under pressure and fairly dry onto the second mould or moulds. By doing this, some of the exterior surface of the second moulds will initially be pitted due to the abrasive nature of the concrete, but this is soon overlayed with additional gunite to the required thickness. Additives may be mixed in with the concrete in order to improve its qualities, for example lime increases porosity and softness, and citric acid retards curing time. The thickness of the second mould will, of course, vary from application to application, but a thickness of between half an inch (say 1.2 cm) to two inches (say 5.1 cm) of fibrous plaster may be typical. Somewhere between 5 cm and 15.5 cm (between two and six inches) of gunite may then applied to the second mould to provide the required reinforcement. Not only single storey buildings can be erected in this way, but also multi¬ storey buildings. Of course, additional reinforcing pillars, either of concrete or steel, for example, may be necessary. These would, however, ideally be incorporated in the areas between adjacent second moulds and should not, therefore, be seen in the completed structure. Furthermore, in certain applications, it may be necessary to incorporate steel- rods in the reinforcing layer to increase further the strength of the layer. An insulating layer is preferably applied to the outside of the reinforcing layer. The insulation may take the form of pumice (possibly in the form of beads or powder) in a cement mix or, alternatively, a foam insulation, both of which can be easily sprayed onto the reinforcing layer. An outer decorative layer may be applied directly onto the reinforcing layer or, alternatively, onto the insulating layer. Clearly any suitable form of decorative layer may be used, but a ceramic decorative layer is particularly preferred. This is because ceramics can be decorative and colourful, yet are relatively cheap to manufacture, are chemically inert and are very durable. A specific embodiment of the present invention is now described, by way of example only, with reference to accompanying drawing which shows a sectional side view of a part of a house manufactured using the method of the present invention. With reference to the drawing, a portion of a building, such as a house, is shown comprising a master bedroom 1, a dressing area 3, a bath/wash room 5, a utility room 7 and a corridor 9 between a kitchen (not shown) and a dining room (not shown) . The house shown in the drawing includes only a ground floor level and a first floor level; houses or other structures having additional levels could, however, equally well be erected. When erecting the house, initially a concrete raft 11 with steel reinforcement is laid on a suitable site. A plurality of plaster moulds or casts 13 are formed, perhaps adjacent to the site, on corresponding first moulds (not shown) made of any suitable material. The first moulds, which may be formed primarily from fiberglass so that they can be accurately defined, ideally have a silicone rubber skin over their contact surfaces. This skin enables the plaster cast (or second mould) 13 to be released easily from the first mould to produce a high quality finished surface 15 on the second plaster mould 13. These high quality finished surfaces 15 of the plaster moulds 13 form the internal surfaces of the rooms 1-9 of the house. By including the silicone rubber skin on the first moulds, " pitting and crazing of the plaster is avoided. Although by no means essential, quick release bracing may be used to support the first mould during formation of the second mould. The bracing can simply be released when the second mould has set sufficiently, thereby facilitating removal of the first mould from the second mould. This arrangement therefore involves the use of a collapsible first mould to permit removal of an entire cast 13. In an alternative arrangement, the first moulds are not collapsible, and instead the casts 13 are split and removed therefrom in segments, e.g. in two vertical halves, which are subsequently bonded together to form the rooms. The dividing line between the two halves can then be easily plastered over after assembly. As can be seen from the drawing, the bath/wash room 5 and the utility room 7 have essentially the same shape and, therefore, can be erected from plaster moulds 13 formed on the same first mould. In this regard, it is likely that the bath/wash room 5 and the utility room 7 will each be formed in two halves so that the plaster moulds 13 can be readily removed from the first mould. One of the second moulds 13 used to form the bath/wash room 5 may have an area broken away during erection to produce a window opening 17. Alternatively, and probably in practice more likely, an additional first mould may be used to produce a plaster cast 19 shaped to form the window opening. In any event, as will be appreciated, a number of plaster casts 13 are produced from first moulds, and the plaster casts 13 are then assembled on the concrete raft 11 in the desired manner. Once the plaster casts have been assembled, the internal services, such as electrical conduits 16, wiring for recessed lights 18, plumbing, etc., for the various rooms 5, 7, 9 can be installed simply by drilling through the plaster casts 13, which are approximately one inch (2.5 cm) in thickness. When the services have been installed, a reinforcing layer 21, ideally of gunite, is sprayed over the external surfaces 23 of the plaster casts 13. Three inches (7.6 cm) of gunite, possibly with steel reinforcement if necessary, is applied to the external surfaces 23 of the plaster casts 13. When the gunite cures, it bonds with the plaster cast 13 and sets to provide sufficient rigidity and strength to satisfy building regulations . Concrete or steel columns 25 are erected between adjacent rooms to support the first floor of the building. The spaces between the concrete columns 25 and the surface of the set gunite 21 is then filled with insulating material 27, such as pumice (in the form of beads or powder) or foam. This can act either to keep heat in or to keep the rooms cool, depending upon the climate. Although clearly a large number of first moulds will be required to provide the required number of curvilinear shaped plaster casts 13 for a complete house, each first mould can be re-used many times because it is not included in the completed house and, therefore, does not need to be destroyed for removal therefrom. This is a marked improvement over the prior art. Once the ground floor rooms have been erected as described, a concrete first floor 29 can be laid supported by the concrete columns 25 on top of the ground floor rooms. The first floor rooms 1, 3 can then be erected using plaster moulds 13 formed on the ' same or different first moulds in the same way as described for the ground floor rooms 5, 7, 9. Once the complete house has been erected, an exterior surface 31 is applied to the house to provide an attractive and hard wearing finish. As shown in the drawing, the exterior surface 31 in this embodiment is a decorative ceramic. Other suitable exterior finishes could, of course, alternatively be used. Although the specific embodiment described herein incorporates curvilinear rooms, the method of the present invention could equally well be used for more standard shapes of structure without departing from the scope of the present invention. Whatever the structure, however, it is a simple matter to erect the structure by using the method of this invention. In this regard, it is envisaged that a five bedroom house may be erected using this method in approximately 10-12 hours. This is clearly very quick and is a distinct advantage of the present invention over normal building methods, which take significantly longer. Furthermore, the shape of the rooms of a house are simply dictated by the shape of the first moulds and can, therefore, be almost any shape. Even if a plaster cast 13 cracks or chips slightly during installation, this is not a problem because the fault can simply be remedied by plastering over, as one would in any normal house. Although it is envisaged that the plaster casts 13 are likely to be formed near to the final site of the structure, this does not have to be the case and the plaster casts 13 could be manufactured in large quantities at a central factory and transported to the required sites, as necessary. It will of course be understood that the present invention has been above described purely by way of example, and that modifications of detail can be made within the scope of the invention.

Claims: CLAIMS 1. A method of manufacturing structures comprising the steps of: (a) forming a first mould having a release surface; (b) applying plaster or a plaster substitute to the release surface of the first mould to produce a second mould; (c) removing the second plaster mould from the first mould to reveal a finished surface produced by contact with the release surface; (d) arranging the second plaster mould in a desired position away from the first mould; and (e) applying a reinforcing layer onto the opposite surface of the plaster mould to the finished surface such that the reinforcing layer cures and bonds to the plaster mould to produce a structure having an integral finished plaster or plaster substitute surface. 2. A method as claimed in claim 1, wherein a plurality of the second moulds are produced either from the same first mould or from different first moulds. 3. A method as claimed in claim 1 or claim 2, further comprising, between steps (d) and (e) , the step of installing services into the structure through the second plaster mould, which services are held in position by the reinforcing layer once it is applied and cured. 4. A method as claimed in any preceding claim, wherein the reinforcing layer is concrete. 5. A method as claimed in claim 4, wherein the reinforcing layer is a sprayed concrete, such as gunite. 6. A method as claimed in claim 5, wherein the gunite is sprayed under pressure and relatively dry onto the second mould or moulds. 7. A method as claimed in any preceding claim, wherein the release surface is provided by a silicone rubber skin. 8. A method as claimed in any preceding claim, wherein plaster is applied to the release surface of the first mould to produce a second mould having a thickness of between 1.2 cm and 5.1 cm. 9. A method as claimed in any preceding claim, " wherein a reinforcing layer is applied to the second plaster mould to produce a reinforcing layer having a thickness of between 5 cm and 15.5 cm. 10. A method as claimed in any preceding claim, further including, after step (e) , the step of spraying an insulation layer over the reinforcing layer. 11. A method as claimed in any preceding claim, further including, after step (e) , the step of applying an aesthetic exterior surface finish to the structure. 12. A method as claimed in claim 11, wherein the aesthetic exterior surface finish is formed using decorative ceramics. 13. A method as claimed in any preceding claim in which the second mould is split into at least two segments to facilitate removal thereof from the first mould, each segment being assembled with at least one complementary segment prior to applying the reinforcing layer.- 14. A structure formed using a method according to any preceding claim, wherein the structure is a house, the internal walls of which are provided by the surfaces of the second moulds. - il ¬ ls. A structure as claimed in claim 14, wherein the house has a ground floor and one or more floors above. 16. A structure as claimed in claim 15, wherein the floors above the ground floor are supported by means of concrete columns situated between adjacent rooms on the ground floor of the house.

Inventors: DEAN WILLIAM ROGER, DEAN, WILLIAM, ROGER
Applicants: CURVED SPACE LTD, DEAN WILLIAM ROGER, CURVED SPACE LIMITED, DEAN, WILLIAM, ROGER
Application year: 1994
Main classification: E04B1
IPC codes: E04B1